• Journal of Applied Biological Chemistry
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• v.61 no.4
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• pp.335-340
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• 2018

Hemoglobin (Hb) is a member of heme-protein that can perform catalytic non-specific chain reaction in the presence of hydrogen peroxide ($H_2O_2$). Catalytic ability of Hb to degrade pyrene was demonstrated using soil contaminated with $^{14}C$ pyrene and 10 mg pyrene /kg soil. The composition of soil was similar to previously used soil except that it had lower organic carbon content. Bench scale laboratory tests were conducted in the presence of buffer only, $H_2O_2$ only, or Hb with $H_2O_2$ for 24 h. After 24 h reaction, 0.1 and 1.3% of $^{14}C$ pyrene in contaminated soil were mineralized with $H_2O_2$ only or Hb plus $H_2O_2$. No mineralization to $^{14}CO_2$ was detected with buffer only. Approximately 12.2% of pyrene was degraded in the presence of $H_2O_2$ only while 44.0% of pyrene was degraded in the presence of Hb plus $H_2O_2$ during 24 h of catalytic reaction. When degradation intermediate products were examined, two chemicals were observed in the presence of $H_2O_2$ only while 25 chemicals were found in the presence of Hb plus $H_2O_2$. While most degradation products were simple hydrocarbons, four of the 27 chemicals had aromatic rings. However, none of these four chemicals was structurally related to pyrene. These results suggest that Hb catalytic system could be used to treat pyrene-contaminated soil as an efficient and speedy remediation technology. In addition, intermediate products generated by this system are not greatly affected by composition change in soil organic matter content.

• Journal of Korean Society on Water Environment
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• v.27 no.1
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• pp.98-103
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• 2011

Photocatalysis using UV light and catalysts is an attractive low temperature and non-energy- intensive method for remediation of a wide range of chemical contaminants like chloroform (CF). Recently development of environmental friendly and sustainable catalytic systems is needed before such catalysts can be routinely applied to large-scale remediation or drinking water treatment. Titanium dioxide is a candidate material, since it is stable, highly reactive, and inexpensive. Diatoms are photosynthetic, single-celled algae that make a microscale silica shell with nano scale features. These diatoms have an ability to biologically fabricate $TiO_2$ nanoparticles into this shell in a process that parallels nanoscale silica mineralization. We cultivated diatoms, metabolically deposited titanium into the shell by using a two-stage photobioreactor and used this biogenic $TiO_2$ to this study. In this study we evaluated how effectively biogenic $TiO_2$ nanoparticles transform CF compared with chemically-synthesized $TiO_2$ nanoparticlesthe and effect of pretreatment of diatom-produced $TiO_2$ nanoparticles on photocatalytic transformation of CF. The rate of CF transformation by diatom-$TiO_2$ particles is a factor of 3 slower than chemically-synthesized one and chloride ion production was also co-related with CF transformation, and 79~91% of CF mineralization was observed in two $TiO_2$ particles. And the period of sonication and mass transfer due to particle size, evaluated by difference of oxygen tention does not affect on the CF transformation. Based on the XRD analysis we conclude that slower CF transformation by diatom-$TiO_2$ might be due to incomplete annealing to the anatase form.

• Proceedings of the Korean Geotechical Society Conference
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• 1992.12a
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• pp.1-18
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• 1992

The contaminatlon of soil and groundwater by leachate from impmperly managed landfills, or by cheiicals and gasoline leaked flu underground storage tanks has buou a serious urldwide environmental problei. Most of those contaminants are adsorptive and absorptive into soul, while they are hardly soluble in water. Thus, the rate of self purification is very slow, causing persistent problems in water use and environmental protection when the contamination is left untreated. Biological remediatlon technologies utilize the ertraordlnary caperbllity of microorganisms In degrading a tilde spectrum of organic compounds. Among them, an in situ bioremediation technology Involves injection of supplementary materials into the subsurfce in order to bring about a significant Increase in the microbial activity. The Increased microbial activity helps remove the pollutants in situ, that is, without digging out contaminants, soil, or water. This paper focused on the features, possibilities, and limitations of the bioremedition technology.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.1
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• pp.67-77
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• 2011

Heavy metal remediation in shooting range soil is a challenge over the world. The excessive Pb accumulation in the soil can deteriorate soil quality and fertility. The objectives of this research were to evaluate the efficiency of biochar (BC) in improving the physicochemical and biological properties of the soil and to evaluate its effect on Pb availability in a military shooting range soil. Sandy loam soil was collected from shooting range of Gyeonggi Province, South Korea and was incubated for 30 days with different application rates (0-30% w $w^{-1}$) of BC. The results showed that the addition of BC increased aggregate stability, nitrogen (N) and phosphorus (P) contents, and enzyme activities in soil. Sequential extraction showed that residual and organic bound fractions in the soil amended with BC increased by 33.1 and 16.7%, respectively, and the exchangeable fraction decreased by 93.7% in the soil amended with BC, compared to the unamended soil. We concluded that the application of BC could not only improve physicochemical and biological soil qualities but also stabilize Pb in a shooting range soil.

• Journal of Korea Soil Environment Society
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• v.2 no.1
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• pp.3-12
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• 1997

Phytoremediation, using plants to remediate toxic organic and inorganic pollutants in contaminated soils, is an emerging technology for environmental cleanup. Three strategies of this technology are applicable to the remediation of toxic heavy metals, radionuclides, and toxic organic pollutants: They are (1) phytoextraction, in which plants anumulate the contaminants and are harvested for the downstream processing; (2) phytodegradation, in which plant-released enzymes or plant-associated microorganisms convert toxic pollutants into non-toxic materials; and (3) phytostabilization, in which toxic pollutants are precipitated from solution or absorbed in either the plant tissue or the soil matrix. Phytoremediation is more effective and less expensive than other current treatment technologies.

• Advances in environmental research
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• v.1 no.2
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• pp.97-108
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• 2012

Microbial degradation of hydrocarbons is found to be an attractive process for remediation of contaminated habitats. However the poor bioavailability of hydrocarbons results in low biodegradation rates. Cyclodextrins are known to increase the bioavailability of variety of hydrophobic compounds. In the present work we purified the Cyclodextrin Glucanotransferase (CGTase) enzyme which is responsible for converting starch into cyclodextrins and studied its role on biodegradation of diesel oil contaminated soil. Purification of CGTase from Enterobacter cloacae was done which resulted in 6 fold increase in enzyme activity. The enzyme showed maximum activity at pH 7, temperature $60^{\circ}C$ with a molecular weight of 66 kDa. Addition of purified CGTase to the treatment setup with Pseudomonas mendocina showed enhanced biodegradation of diesel oil ($57{\pm}1.37%$) which was similar to the treatment setup when added with Pseudomonas mendocina and Enterobacter cloacae ($52.7{\pm}6.51%$). The residual diesel oil found in treatment setup added with Pseudomonas mendocina at end of the study was found to be $73{\pm}0.21%$. Immobilization of Pseudomonas mendocina on alginate containing starch also led to enhanced biodegradation of hydrocarbons in diesel oil at 336 hours.

• Advances in environmental research
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• v.1 no.3
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• pp.201-210
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• 2012

The bioavailability of sorbed organic contaminants is one of the most important factors used to determine their fate in the environment. This study was conducted to evaluate the bioavailability of slow-desorbable naphthalene in soils. An air sparging system was utilized to remove dissolved (or desorbed) naphthalene continuously and to limit the bacterial utilization of dissolved naphthalene. A biological air sparging system (air sparging system with bacteria) was developed to evaluate the bioavailability of the slow-desorption fraction in soils. Three different strains (Pseudomonas putida G7, Pseudomonas sp. CZ6 and Burkholderia sp. KM1) and two soils were used. Slow-desorbable naphthalene continuously decreased under air sparging; however, a greater decrease was observed in response to the biological air sparging system. Enhanced bioavailability was not observed in the Jangseong soil. Overall, the results of this study suggests that the removal rate of slow-desorbable contaminants may be enhanced by inoculation of degrading bacteria into an air sparging system during the remediation of contaminated soils. However, the enhanced bioavailability was found to depend more on the soil properties than the bacterial characteristics.

• Journal of Soil and Groundwater Environment
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• v.10 no.2
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• pp.28-34
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• 2005

The aim of this article is to assess the application characteristics of the site by remediating oil-contaminated area using DSB (Deep-site Biopile) system. In the contaminated area, the soil was composed of penetrable sand and the leaked oil was spread widely (total 7,201 cubic meters) through 2.5 meter deep underground water flow. DSB system was operated for 30 minutes intervals for 24 hours in a day (30 minutes opεration and 30 minutes stop). To check contamination level change in the contaminated area after DSB system was operated, samples were taken. The result from the site shows that BTEX/TPH contamination level was dropped 50% after 30-day operation of DSB system, and that contamination level was dropped below contamination level check standard after 165 days and the remediation was completed. Unlike traditional biological remediation methods DSB system could efficiently process soil and water which were contaminated by high levels of oil compounds.

• Journal of Applied Biological Chemistry
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• v.58 no.2
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• pp.157-174
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• 2015

Stabilization of metals in contaminated soils using various waste materials has been reported. Alkaline materials (limes, shells, industrial byproducts, etc.), phosphorous (P) containing materials (animal bones, phosphate rock, etc.), organic materials (composts, manures, biochars, etc.) and others (zerovalent iron, zeolite, etc.) were widely evaluated to ensure its effectiveness/applicability of stabilization of metals in soils. Stabilization mechanisms of those materials above were partially revealed, but the related literatures are still lacked and not sufficient for approaching to long-term stability/applicability in the field. The aims of this review are to summarize current knowledge of metal stabilization in contaminated soils using various waste materials and to suggest a direction for future field research.

• Journal of Soil and Groundwater Environment
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• v.12 no.2
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• pp.27-36
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• 2007

A recent study showed that MTBE can be degraded by Fenton's Reagent (FR). The treatment of MTBE with FR, however, has a definite limitation of extremely low pH requirement (optimum pH $3{\sim}4$) that makes the process impracticable under neutral pH condition on which the ferrous ion precipitate forming salt with hydroxyl anion, which result in the diminishment of the Fenton reaction and incompatible with biological treatment. Consequently, this process using only FR is not suitable for in-situ remediation of MTBE. In order to overcome this limitation, modified Fenton process using NTA, oxalate, and acetate as chelating reagents was introduced into this study. Modified Fenton reaction, available at near neutral pH, has been researched for the purpose of obtaining high performance of oxidation efficiency with stabilized ferrous or ferric ion by chelating agent. In the MTBE degradation experiment with modified Fenton reaction, it was observed that this reaction was influenced by some factors such as concentrations of ferric ion, hydrogen peroxide, and each chelating agent and pH. Six potential chelators including oxalate, succinate, acetate, citrate, NTA, and EDTA were tested to identify an appropriate chelator. Among them, oxalate, acetate, and NTA were selected based on their remediation efficiency and biodegradability of each chelator. Using NTA, the best result was obtained, showing more than 99.9% of MTBE degradation after 30 min at pH 7; the initial concentration of hydrogen peroxide, NTA, and ferric ion were 1470 mM, 6 mM, and 2 mM, respectively. Under the same experimental condition, the removal of MTBE using oxalate and acetate were 91.3% and 75.8%, respectively. Optimum concentration of iron ion were 3 mM using oxalate which showed the greatest removal efficiency. In case of acetate, $[MTBE]_0$ decreased gradually when concentration of iron ion increased above 5 mM. In this research, it was showed that modified Fenton reaction is proper for in-situ remediation of MTBE with great efficiency and the application of chelatimg agents, such as NTA, was able to make the ferric ion stable even at near neutral pH. In consequence, the outcomes of this study clearly showed that the modified Fenton process successfully coped with the limitation of the low pH requirement. Furthermore, the introduction of low molecular weight organic acids makes the process more available since these compounds have distinguishable biodegradability and it may be able to use natural iron mineral as catalyst for in situ remediation, so as to produce hydroxyl radical without the additional injection of ferric ion.